Internal combustion engine



Apr 7, 1936. .A BCHI 2,036,989

INTERNAL COMBUSTION ENGINE Filed April 2l, 1927 Patented Apr. 7, 1936 I Alfred Biiclii, Winterthur, Switzerland "Application Aprii 21, 1927, serial No. 185,558

rn switzerland .api-n so, 192e l. Cla-im. (Cl. 12%140) engine with an exhaust gas driven precompressor f as will be explained hereinafter. If for instance full load is .on the engine and the pressure of the charging air drops all of a sudden (break w down of the precompressor, leak in the pressure piping, closing of air valves or the like), the pressure at the beginning of the compression stroke becomes lower and also the compression pressure, in other words the output of the internal combustion engine decreases. As the load is still on, the revolutions drop, the ordinary governor starts now to act in such a' manner as to-feed more fuel to the'combustion cylinders in order to speed the engine up again. Although the air pressure has dropped, more and more fuel is fed to the cylinders which results in bad combustion, after-burning and very high temperatures, which may result in severe damage especially to cylinder head and valves. ln this moment the device 3@ according to this invention starts to act. The

fuel supply to the combustion cylinders is checkedv by means described hereinafter, so that at each Value of the air pressure only one fixed amount of fuel is supplied to the combustion cylinders regardless ofthe position of the governor, where-v by this amount of fuel is the higher, the higher the pressure of the precompreed air is. lin other words, the ratio, weight of air divided by weight of fuel, does not drop below a certainA 4*@ limit, allowing a safe operation of the internal combustion engine. I want to point out, that the device checking the fuel supply must not absolutely be operated by the pressure of the charging air but must also be operated by the pressure of 5 the exhaust gas from the internal combustion engine. In the accompanying drawing constructional examples of devices for carrying out the invention are shown.

60 Figure l shows an arrangement of a multicylinder internal combustionengine according to the invention.

Figures 2, 3 and i show detailed modied forms .of the controlling apparatus indicated at' 8 and a@ 9 in Figure 1. l

Figure 5 shows a plan of the device of Fig ure 2, but including also the eccentric 2l.

In Figure 1, I is an internal combustion engine having the cylinders 2, 3, ll, 5, t and driving a generator l. 8 is the governor of the internal combustion engine, regulating the fuel quantity supplied to the combustion cylinders by the fuel pump 9 and is of conventional form. i@ denotes the charging compressor driven by an exhaust gas turbine il. From the internal combustion engine i the exhaust gases are led to the turbine il by theexhaust pipe I2. To by-pass the exhaust gases to the atmosphere, a' pipe i3 branches on the pipe I2 and can be opened or closed to the atmosphere by means `of valve it. The comw pressor delivers the charging air through pipe I5, common to all cylinders, to the internal combustion engine. The engine can also draw in air directly from the latmosphere by opening valve i6, for instance when the engine is running idle or at small loads. Numeral Il denotes an electric motor which can be switched on and drives the charging compressor whenever it is necessary. In order to limit the delivery of the fuel pump 9 to the internal combustion engine a pipe it leads from the charging air pipe i5 to a device described hereinafter, preventing more fuel being fed to the engine thancan be admitted if the combustion temperatures are not to exceed a fixed maximum. 30 Figure 2 shows such a device in detail. The internal combustion engine, which is omitted for clearness sake, is provided with a fuel pump 9, with piston t2 actuated by eccentric 20 on shaft 5 2t.` 23 is the delivery and 2i the suction valve. 25 is the fuel delivery pipe leading to the cylinders of the internal combustion engine. The fuel pump 9 is regulated by the governor 8, which shifts an eccentric 2T on the rotating 4@ shaft 2t, see also Figure 5, so that the regulating member 28 allows to close suction valve 24 earlier or later. The eccentric 2l forms a sleeve connected to the weights of the governor with the linksE-i. According to each position of these weights fulcrumed at 53, corresponds a position of the eccentric 2l. The governor 8 and eccentric 2l rotate with the cam shaft 26, the governor being keyed to `said shaft. 'Ihe quantity of fuel fed to the combustion cylinders is regulated by the earlier or later closing of the suction valve 2t. Pipe 3| leading to the pump 9 is the suction pipe and can be closed by means of valve 32. The device according to the present invention comprises a cylinder 33 and pipe i8 connected 55 one of the pressure stages of the blower through the pipe I8' (Figure l) In the cylinder33 moves ka piston 34 with the piston rod 35 which acts by l means of levers 36 on the shaft 38. Lever 28 is eccentric on shaft `38, so that by turning the latter, the position of lever 29 can be varied. 'I'he lever 29 is acted upon by the member 28 which in turn is acted upon by a sleeve surrounding the ec-4 centric 21 so that the suction valve 24 is operated by the rocking motion of the lever 29 to control the supply of fuel in accordance with the relative position of the eccentric 21 and this as a projection of lever 29 influences the closing of the suction valve 24, the closing of this suction valve 24 can be varied by varying the position of lever 23. In other words the suction valve 24 can be closed later or earlier quite independently of the governor, so that more or less fuel can be supplied to the internal combustion engine without any preceding action of the engine governor. n one side of piston 34 acts the air pressure and on the other a spring 31. If the charging air pressure drops, the pressure on the piston drops also and piston 34 rises, shaft 28 is turned by means of levers l3G, so that the suction valve 24 is closed later than previously and less fuel fed to the internal combustion engine. Piston 34 may also be provided with a handwheel 38 on the threaded piston rod 35 allowing for adjustment by hand. For instance with a right hand thread on rod 35, piston 34 can be pulled downwards by turning the handwheel 38 to the right. 'This arrangement allows to adjust the fuel pump for full admission, even when the full charging pressure in pipe I8 or above the piston 34 is not yet reached, If the handwheel 38 is turned to the left it moves away from the cover of cylinder 33 and piston 34 becomes free to take the equilibrium position. The lower end of the cylinder 33 is connected to the exhaust pipe I2 or one of thepressure stages of the exhaust gas turbine by means of pipe I9 or I3' respectively. Equilibrium of the forces on either side of piston 34 therefore takes place when spring force and force due to the exhaust gas pressure are equal to the forces due to the air pressure. `The fuel admission to the internal combustion engine is made dependent on both the ratio of air and exhaust pressure. 'Ihis arrangement has the big advantage, that at a sudden rise of the exhaust pressure withoutacorresponding rise in the air pressure vthe fuel admission to the internal combustion engine is reduced as the piston rises, so that the fuel admission to the internal combustion engine can be entirely stopped. On the other hand, when the charging pressure is high, piston 34 is forced downward and the fuel quantity fed to the internal combustion engine increases. Thus, with the arrangement shown in'Figure 2 the maximum fuel supply to the internal combustion engine is limited by the charging air pressure in such a way, that the fuel quantity allowed to be pumped to the combustion cylinders cannot be exceeded. During normal performance of the engine the amount of fuel fed to the combustion cylinders is inside of the maximum allowable quantity. Up to this maximum quantity the governor of the engine can so influence the regulating linkage that any amount of fuel is delivered to the internal combustion engine.y The maximum allowable quantity can never be exceeded, as the device according to the invention acts upon the suction valve of the fuel pump as soon as'this maximum amount is reached.

In Figure 3 a similar arrangement to that in Figure 2 is shown, also for limiting the maximum fuel supply. Piston 34 moves in a horizontal cylinder 33 and its movement is transmitted by rod 35 to the lever 39. If piston 34 moves to the right lever 39 turns anti-clockwise, thereby opening the suction valve so that the delivery of the fuel pump is partly or entirely interrupted. This occurs when the pressure in the charging pipe I8 falls below the admissible value or when the exhaust pressure in pipe I9 becomes too big. With handwheel 38 the pressure of spring 31 can be increased and piston 34 moved to the right, so that by means of crank lever 39 the suction valve 24 can be opened. An additional hand ad- Justing device 40, 4I'is provided for, by means of which the fuel delivery can be varied independently of the arrangement 33, 34 and 35. An arrangement of this kind is particularly suitable for engines of vehicles. For the rest the arrangement is as in Figure 2.

The device according to the invention may also be applied to engines in which the fuel supply is regulated by hand, as e. g., in marine engines and railway engines. Such a constructional form is shown in Figure 4. Numerals 48, 4I represent the hand regulating device for the fuel pump 9. By moving lever 48 shaft 4I is turned whereby the fuel quantity pumped tothe engine cylinders is affected. Lever 48 is keyed to shaft 4|, but lever .44 is loose thereon. Lever 48 is provided with a nose 54 that strikes against a part of the lever 44 so that the movement of the lever 48 is limited by the lever 44, whereas the position of the lever 44 depends on the air and exhaust pressures. The shaft 4I is similar to shaft 38 and is in a similar manner provided with eccentrics. Lever 48 can be fixed in any position on segment 43. The means 33, 34, 35 and 31 are arranged to act in such a-manner on a lever 44, as described that this lever prevents lever 48 from being turned to the right beyond a determined position. The lower the charging air pressure and the higher the exhaust pressure the more piston 34 is pushed over to the left thereby moving lever 44 also to the left. Lever 44 pushes lever 48 more to the left, corresponding to a position where less fuel is pumped to the combustion cylinders. When the charging pressure rises, a greater fuel supply is permissible, piston 34 moves to the right and also lever 44, being directly connected to piston 34. It is therefore possible to turn lever 48 more to the right and increase the fuel supply to the combustion cylinders. In an arrangement according to Figure 'l the fuel delivery is thus adjusted by hand but the maximum admissible fuel quantity is limited in dependency 'of the charging and exhaust pressure. To move piston 34 also at will handwheel 38 is provided for.

In Figure 2 the arrangement acts as safety device, in Figure v3 as cut-off device, but it may also be constructed so as to act as a safety device only. In this latter case the arrangement may be such, that when the charging pressure, is low, it is impossible to supply more than a certain, allowable quantity of fuel to the combustion cylinders, whereby the allowable quantity increases with increasing charging air pressure. If the charging pressure drops the arrangement acts "in such a way that the allowabley fuel quantity is reduced.

What I claim is: Y An internal combustion engine comprising in combination a combustion cylinder, a. turbine, an

air inlet duct and an exhaust gas duct delivering exhaust gas to said turbine, a charging blower driven by said turbine for delivering a compressed charge to said cylinder; a fuel pump for delivering fuel to said cylinder, an inlet valve having a stem to control the inlet of fuel to said pump,

1o a safety device including a iiuid pressure respon- ALFREDBCHI. 10 

